/*-
 * Copyright (c) 2001 Alexey Zelkin <phantom@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */


#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "strfmon.h"

/* internal flags */
#define NEED_GROUPING           0x01    /* print digits grouped (default) */
#define SIGN_POSN_USED          0x02    /* '+' or '(' usage flag */
#define LOCALE_POSN             0x04    /* use locale defined +/- (default) */
#define PARENTH_POSN            0x08    /* enclose negative amount in () */
#define SUPRESS_CURR_SYMBOL     0x10    /* suppress the currency from output */
#define LEFT_JUSTIFY            0x20    /* left justify */
#define USE_INTL_CURRENCY       0x40    /* use international currency symbol */
#define IS_NEGATIVE             0x80    /* is argument value negative ? */

/* internal macros */
#define PRINT(CH) do {                                          \
        if (dst >= s + maxsize)                                 \
                goto e2big_error;                               \
        *dst++ = CH;                                            \
} while (0)

#define PRINTS(STR) do {                                        \
        char *tmps = STR;                                       \
        while (*tmps != '\0')                                   \
                PRINT(*tmps++);                                 \
} while (0)

#define GET_NUMBER(VAR) do {                                    \
        VAR = 0;                                                \
        while (isdigit((unsigned char)*fmt)) {                  \
                VAR *= 10;                                      \
                VAR += *fmt - '0';                              \
                fmt++;                                          \
        }                                                       \
} while (0)

#define GRPCPY(howmany) do {                                    \
        int i = howmany;                                        \
        while (i-- > 0) {                                       \
                avalue_size--;                                  \
                *--bufend = *(avalue+avalue_size+padded);       \
        }                                                       \
} while (0)

#define GRPSEP do {                                             \
        *--bufend = thousands_sep;                              \
        groups++;                                               \
} while (0)

static void __setup_vars(int, char *, char *, char *, char **);
static int __calc_left_pad(int, char *);
static char *__format_grouped_double(double, int *, int, int, int);

ssize_t
strfmon(char * __restrict s, size_t maxsize, const char * __restrict format,
    ...)
{
        va_list         ap;
        char            *dst;           /* output destination pointer */
        const char      *fmt;           /* current format position pointer */
        struct lconv    *lc;            /* pointer to lconv structure */
        char            *asciivalue;    /* formatted double pointer */

        int             flags;          /* formatting options */
        int             pad_char;       /* padding character */
        int             pad_size;       /* pad size */
        int             width;          /* field width */
        int             left_prec;      /* left precision */
        int             right_prec;     /* right precision */
        double          value;          /* just value */
        char            space_char = ' '; /* space after currency */

        char            cs_precedes,    /* values gathered from struct lconv */
                        sep_by_space,
                        sign_posn,
                        *signstr,
                        *currency_symbol;

        char            *tmpptr;        /* temporary vars */
        int             sverrno;

        va_start(ap, format);

        lc = localeconv();
        dst = s;
        fmt = format;
        asciivalue = NULL;
        currency_symbol = NULL;
        pad_size = 0;

        while (*fmt) {
                /* pass nonformating characters AS IS */
                if (*fmt != '%')
                        goto literal;

                /* '%' found ! */

                /* "%%" mean just '%' */
                if (*(fmt+1) == '%') {
                        fmt++;
        literal:
                        PRINT(*fmt++);
                        continue;
                }

                /* set up initial values */
                flags = (NEED_GROUPING|LOCALE_POSN);
                pad_char = ' ';         /* padding character is "space" */
                left_prec = -1;         /* no left precision specified */
                right_prec = -1;        /* no right precision specified */
                width = -1;             /* no width specified */
                value = 0;              /* we have no value to print now */

                /* Flags */
                while (1) {
                        switch (*++fmt) {
                                case '=':       /* fill character */
                                        pad_char = *++fmt;
                                        if (pad_char == '\0')
                                                goto format_error;
                                        continue;
                                case '^':       /* not group currency  */
                                        flags &= ~(NEED_GROUPING);
                                        continue;
                                case '+':       /* use locale defined signs */
                                        if (flags & SIGN_POSN_USED)
                                                goto format_error;
                                        flags |= (SIGN_POSN_USED|LOCALE_POSN);
                                        continue;
                                case '(':       /* enclose negatives with () */
                                        if (flags & SIGN_POSN_USED)
                                                goto format_error;
                                        flags |= (SIGN_POSN_USED|PARENTH_POSN);
                                        continue;
                                case '!':       /* suppress currency symbol */
                                        flags |= SUPRESS_CURR_SYMBOL;
                                        continue;
                                case '-':       /* alignment (left)  */
                                        flags |= LEFT_JUSTIFY;
                                        continue;
                                default:
                                        break;
                        }
                        break;
                }

                /* field Width */
                if (isdigit((unsigned char)*fmt)) {
                        GET_NUMBER(width);
                        /* Do we have enough space to put number with
                         * required width ?
                         */
                        if (dst + width >= s + maxsize)
                                goto e2big_error;
                }

                /* Left precision */
                if (*fmt == '#') {
                        if (!isdigit((unsigned char)*++fmt))
                                goto format_error;
                        GET_NUMBER(left_prec);
                }

                /* Right precision */
                if (*fmt == '.') {
                        if (!isdigit((unsigned char)*++fmt))
                                goto format_error;
                        GET_NUMBER(right_prec);
                }

                /* Conversion Characters */
                switch (*fmt++) {
                        case 'i':       /* use international currency format */
                                flags |= USE_INTL_CURRENCY;
                                break;
                        case 'n':       /* use national currency format */
                                flags &= ~(USE_INTL_CURRENCY);
                                break;
                        default:        /* required character is missing or
                                           premature EOS */
                                goto format_error;
                }

                if (flags & USE_INTL_CURRENCY) {
                        currency_symbol = strdup(lc->int_curr_symbol);
                        if (currency_symbol != NULL)
                                space_char = *(currency_symbol+3);
                } else
                        currency_symbol = strdup(lc->currency_symbol);

                if (currency_symbol == NULL)
                        goto end_error;                 /* ENOMEM. */

                /* value itself */
                value = va_arg(ap, double);

                /* detect sign */
                if (value < 0) {
                        flags |= IS_NEGATIVE;
                        value = -value;
                }

                /* fill left_prec with amount of padding chars */
                if (left_prec >= 0) {
                        pad_size = __calc_left_pad((flags ^ IS_NEGATIVE),
                                                        currency_symbol) -
                                   __calc_left_pad(flags, currency_symbol);
                        if (pad_size < 0)
                                pad_size = 0;
                }

                asciivalue = __format_grouped_double(value, &flags,
                                left_prec, right_prec, pad_char);
                if (asciivalue == NULL)
                        goto end_error;         /* errno already set     */
                                                /* to ENOMEM by malloc() */

                /* set some variables for later use */
                __setup_vars(flags, &cs_precedes, &sep_by_space,
                                &sign_posn, &signstr);

                /*
                 * Description of some LC_MONETARY's values:
                 *
                 * p_cs_precedes & n_cs_precedes
                 *
                 * = 1 - $currency_symbol precedes the value
                 *       for a monetary quantity with a non-negative value
                 * = 0 - symbol succeeds the value
                 *
                 * p_sep_by_space & n_sep_by_space
                 *
                 * = 0 - no space separates $currency_symbol
                 *       from the value for a monetary quantity with a
                 *       non-negative value
                 * = 1 - space separates the symbol from the value
                 * = 2 - space separates the symbol and the sign string,
                 *       if adjacent.
                 *
                 * p_sign_posn & n_sign_posn
                 *
                 * = 0 - parentheses enclose the quantity and the
                 *       $currency_symbol
                 * = 1 - the sign string precedes the quantity and the
                 *       $currency_symbol
                 * = 2 - the sign string succeeds the quantity and the
                 *       $currency_symbol
                 * = 3 - the sign string precedes the $currency_symbol
                 * = 4 - the sign string succeeds the $currency_symbol
                 *
                 */

                tmpptr = dst;

                while (pad_size-- > 0)
                        PRINT(' ');

                if (sign_posn == 0 && (flags & IS_NEGATIVE))
                        PRINT('(');

                if (cs_precedes == 1) {
                        if (sign_posn == 1 || sign_posn == 3) {
                                PRINTS(signstr);
                                if (sep_by_space == 2)          /* XXX: ? */
                                        PRINT(' ');
                        }

                        if (!(flags & SUPRESS_CURR_SYMBOL)) {
                                PRINTS(currency_symbol);

                                if (sign_posn == 4) {
                                        if (sep_by_space == 2)
                                                PRINT(space_char);
                                        PRINTS(signstr);
                                        if (sep_by_space == 1)
                                                PRINT(' ');
                                } else if (sep_by_space == 1)
                                        PRINT(space_char);
                        }
                } else if (sign_posn == 1)
                        PRINTS(signstr);

                PRINTS(asciivalue);

                if (cs_precedes == 0) {
                        if (sign_posn == 3) {
                                if (sep_by_space == 1)
                                        PRINT(' ');
                                PRINTS(signstr);
                        }

                        if (!(flags & SUPRESS_CURR_SYMBOL)) {
                                if ((sign_posn == 3 && sep_by_space == 2)
                                    || (sep_by_space == 1
                                    && (sign_posn == 0
                                    || sign_posn == 1
                                    || sign_posn == 2
                                    || sign_posn == 4)))
                                        PRINT(space_char);
                                PRINTS(currency_symbol); /* XXX: len */
                                if (sign_posn == 4) {
                                        if (sep_by_space == 2)
                                                PRINT(' ');
                                        PRINTS(signstr);
                                }
                        }
                }

                if (sign_posn == 2) {
                        if (sep_by_space == 2)
                                PRINT(' ');
                        PRINTS(signstr);
                }

                if (sign_posn == 0 && (flags & IS_NEGATIVE))
                        PRINT(')');

                if (dst - tmpptr < width) {
                        if (flags & LEFT_JUSTIFY) {
                                while (dst - tmpptr < width)
                                        PRINT(' ');
                        } else {
                                pad_size = dst-tmpptr;
                                memmove(tmpptr + width-pad_size, tmpptr,
                                    pad_size);
                                memset(tmpptr, ' ', width-pad_size);
                                dst += width-pad_size;
                        }
                }
        }

        PRINT('\0');
        va_end(ap);
        free(asciivalue);
        free(currency_symbol);
        return (dst - s - 1);   /* return size of put data except trailing '\0' */

e2big_error:
        errno = E2BIG;
        goto end_error;

format_error:
        errno = EINVAL;

end_error:
        sverrno = errno;
        if (asciivalue != NULL)
                free(asciivalue);
        if (currency_symbol != NULL)
                free(currency_symbol);
        errno = sverrno;
        va_end(ap);
        return (-1);
}

static void
__setup_vars(int flags, char *cs_precedes, char *sep_by_space,
                char *sign_posn, char **signstr) {

        struct lconv *lc = localeconv();

#if defined _WIN32 && !defined __cygwin__
        if (flags & IS_NEGATIVE) {
#else
        if ((flags & IS_NEGATIVE) && (flags & USE_INTL_CURRENCY)) {
                *cs_precedes = lc->int_n_cs_precedes;
                *sep_by_space = lc->int_n_sep_by_space;
                *sign_posn = (flags & PARENTH_POSN) ? 0 : lc->int_n_sign_posn;
                *signstr = (lc->negative_sign == '\0') ? "-"
                    : lc->negative_sign;
        } else if (flags & USE_INTL_CURRENCY) {
                *cs_precedes = lc->int_p_cs_precedes;
                *sep_by_space = lc->int_p_sep_by_space;
                *sign_posn = (flags & PARENTH_POSN) ? 0 : lc->int_p_sign_posn;
                *signstr = lc->positive_sign;
        } else if (flags & IS_NEGATIVE) {
#endif
                *cs_precedes = lc->n_cs_precedes;
                *sep_by_space = lc->n_sep_by_space;
                *sign_posn = (flags & PARENTH_POSN) ? 0 : lc->n_sign_posn;
                *signstr = (lc->negative_sign == NULL) ? "-"
                    : lc->negative_sign;
        } else {
                *cs_precedes = lc->p_cs_precedes;
                *sep_by_space = lc->p_sep_by_space;
                *sign_posn = (flags & PARENTH_POSN) ? 0 : lc->p_sign_posn;
                *signstr = lc->positive_sign;
        }

        /* Set default values for unspecified information. */
        if (*cs_precedes != 0)
                *cs_precedes = 1;
        if (*sep_by_space == CHAR_MAX)
                *sep_by_space = 0;
        if (*sign_posn == CHAR_MAX)
                *sign_posn = 0;
}

static int
__calc_left_pad(int flags, char *cur_symb) {

        char cs_precedes, sep_by_space, sign_posn, *signstr;
        int left_chars = 0;

        __setup_vars(flags, &cs_precedes, &sep_by_space, &sign_posn, &signstr);

        if (cs_precedes != 0) {
                left_chars += strlen(cur_symb);
                if (sep_by_space != 0)
                        left_chars++;
        }

        switch (sign_posn) {
                case 1:
                        left_chars += strlen(signstr);
                        break;
                case 3:
                case 4:
                        if (cs_precedes != 0)
                                left_chars += strlen(signstr);
        }
        return (left_chars);
}

static int
get_groups(int size, char *grouping) {

        int     chars = 0;

        if (*grouping == CHAR_MAX || *grouping <= 0)    /* no grouping ? */
                return (0);

        while (size > (int)*grouping) {
                chars++;
                size -= (int)*grouping++;
                /* no more grouping ? */
                if (*grouping == CHAR_MAX)
                        break;
                /* rest grouping with same value ? */
                if (*grouping == 0) {
                        chars += (size - 1) / *(grouping - 1);
                        break;
                }
        }
        return (chars);
}

#define BUFFSIZE 255

/* convert double to ASCII */
static char *
__format_grouped_double(double value, int *flags,
                        int left_prec, int right_prec, int pad_char) {

        char            *rslt;
        char            *avalue;
        int             avalue_size;
        char            fmt[32];

        size_t          bufsize;
        char            *bufend;

        int             padded;

        struct lconv    *lc = localeconv();
        char            *grouping;
        char            decimal_point;
        char            thousands_sep;

        int groups = 0;

        grouping = lc->mon_grouping;
        decimal_point = *lc->mon_decimal_point;
        if (decimal_point == '\0')
                decimal_point = *lc->decimal_point;
        thousands_sep = *lc->mon_thousands_sep;
        if (thousands_sep == '\0')
                thousands_sep = *lc->thousands_sep;

        /* fill left_prec with default value */
        if (left_prec == -1)
                left_prec = 0;

        /* fill right_prec with default value */
        if (right_prec == -1) {
                if (*flags & USE_INTL_CURRENCY)
                        right_prec = lc->int_frac_digits;
                else
                        right_prec = lc->frac_digits;

                if (right_prec == CHAR_MAX)     /* POSIX locale ? */
                        right_prec = 2;
        }

        if (*flags & NEED_GROUPING)
                left_prec += get_groups(left_prec, grouping);

        /* convert to string */
        snprintf(fmt, sizeof(fmt), "%%%d.%df", left_prec + right_prec + 1,
            right_prec);
        avalue = malloc (BUFFSIZE);
        if (!avalue)
                return (NULL);
        avalue_size = snprintf(avalue, BUFFSIZE, fmt, value);
        if (BUFFSIZE < avalue_size)
        {
                avalue = realloc (avalue, avalue_size + 1);
                if (!avalue)
                        return (NULL);
                avalue_size = sprintf(avalue, fmt, value);
        }
        if (avalue_size < 0)
                return (NULL);

        /* make sure that we've enough space for result string */
        bufsize = strlen(avalue)*2+1;
        rslt = malloc(bufsize);
        if (rslt == NULL) {
                free(avalue);
                return (NULL);
        }
        memset(rslt, 0, bufsize);
        bufend = rslt + bufsize - 1;    /* reserve space for trailing '\0' */

        /* skip spaces at beginning */
        padded = 0;
        while (avalue[padded] == ' ') {
                padded++;
                avalue_size--;
        }

        if (right_prec > 0) {
                bufend -= right_prec;
                memcpy(bufend, avalue + avalue_size+padded-right_prec,
                    right_prec);
                *--bufend = decimal_point;
                avalue_size -= (right_prec + 1);
        }

        if ((*flags & NEED_GROUPING) &&
            thousands_sep != '\0' &&    /* XXX: need investigation */
            *grouping != CHAR_MAX &&
            *grouping > 0) {
                while (avalue_size > (int)*grouping) {
                        GRPCPY(*grouping);
                        GRPSEP;
                        grouping++;

                        /* no more grouping ? */
                        if (*grouping == CHAR_MAX)
                                break;

                        /* rest grouping with same value ? */
                        if (*grouping == 0) {
                                grouping--;
                                while (avalue_size > *grouping) {
                                        GRPCPY(*grouping);
                                        GRPSEP;
                                }
                        }
                }
                if (avalue_size != 0)
                        GRPCPY(avalue_size);
                padded -= groups;

        } else {
                bufend -= avalue_size;
                memcpy(bufend, avalue+padded, avalue_size);
                if (right_prec == 0)
                        padded--;       /* decrease assumed $decimal_point */
        }

        /* do padding with pad_char */
        if (padded > 0) {
                bufend -= padded;
                memset(bufend, pad_char, padded);
        }

        bufsize = bufsize - (bufend - rslt) + 1;
        memmove(rslt, bufend, bufsize);
        free(avalue);
        return (rslt);
}
